Means and method for classifying and piling sheets



Oct. 5, 1965 w. o. JONES 3,209,892

MEANS AND METHOD FOR CLASSIFYING AND FILING SHEETS Original Filed March29, 1957 7 Sheets-Sheet 1 Fig.2.

INVENTOR Walter 0. Jones W. O. JONES Oct. 5, 1965 MEANS AND METHOD FORCLASSIFYING AND FILING SHEETS 7 Sheets-Sheet 2 Original Filed March 29,1957 INVENTOR Walter 0. Jones 1965 w. o. JONES 3,209,892!

MEANS AND METHOD FOR CLASSIFYING AND FILING SHEETS Original Filed March29. 195'? 7 Sheets-Sheet 4 8 i .3 E N w {I I\ N 1 N :0 :0 I l a q E g g.0 2 :3 H N I I ,1 F x :5 a R H I m o 1" Q g II I 1- 10 a m cu a '3 q- J:J m m E LAVA AA IA D N N 17 In N m INVENTOR Walter 0. Jones W- O. JONESOct. 5, 1965 MEANS AND METHOD FOR CLASSIFYING AND FILING SHEETS OriginalFiled March 29. 19 57 7 Sheets-Sheet 5 mm nmm INVENTOR Walter 0. JonesW. O. JONES Oct. 5, 1965 MEANS AND METHOD FOR CLASSIFYING AND FILINGSHEETS Original Filed March 29. 1957 7 Sheets-Sheet 6 HEW HI :Hn

Oct. 5, 1965 w. o. JONES 3,209,8921

MEANS AND METHOD FOR CLASSIFYING AND FILING SHEETS Original Filed March29, 1957 '7 Sheets$heet 7 Fig l2.

s o o o INVENTOR Walter 0. Jones United States Patent 3,209,892 MEANSAND METHQD FOR CLASSIFYING AND FILING SHEETS Walter 0. Jones, Warren,(lhio, assignor to The Wean Engineering Company, Inc, Warren, Ohio, atcorporation of Ohio Original application Mar. 29, 1957, Ser. No.649,438, new Patent No. 3,104,006, dated Sept. 17, I963. Divided andthis application Sept. 24, 1962, Ser. No. 231,313

5 Claims. (Cl. 198-41) This application is a division of my copendingapplication Serial No. 649,438, filed March 29, 1957, which matured asUnited States Patent No. 3,104,006. Subject matter disclosed but notclaimed herein is claimed in my copending applications Serial Nos.344,297 and 344,420, filed February 12, 1964.

This invention relates to classifying and piling sheets. It isparticularly suited for use with thin flat steel sheets havingvariations of thickness and color, perforations and other defects.

In the steel industry, it has been the practice to roll wide strip ofrelatively thin gauge from basic steel products. Much of the strip iseventually used in sheet form and must be cut into sheets and thenstacked in piles. In many instances various properties of the sheet areimportant to the fin al product, and it becomes necessary to segregateimperfect sheets from those which meet required specifications. Forexample, it is common practice to plate steel strip electrolyticallywith tin. The tin strip is then cut into sheets of desired size for usein making cans or other tinplate products. It has long been importantthat the sheets be of the proper thickness, that the steel have anadherent coating of tin which is unmarked by discolorations, and thatthe strip be free of perforations or pinholes. Other standards may alsobe adopted in particular circumstances. Customarily, gauge means andpinhole detectors of wellknown design are mounted to examine movingstrip coming from the tin line. The strip may also be inspected visuallyfor discolorations. Following these inspections, the strip is passedthrough a shear where it is cut into sheets of the desired length. Thesheets are then separated, sorting out those containing pinholes,discolorations, which are off-gauge and the like. i A sheet classifierand associated gauge means of conventional design is illustrated inKaufman Patent 2,146,581, for example.

The actual separation of the sheets issuing from the shear iscustomarily made by a sheet classifier which mechanically separates andpiles the sheets. A conveyor is ordinarily provided which carries sheetsaway from the shear at a higher speed than strip is entering the shear,thereby leaving an open space between sheets on the conveyor. The sheetsare then diverted at classifying stations to one of several flights ofconveyors which overlap the sheets carried by that flight and depositthem at a piling station. Classifiers are also used in shear lines wherethe sole purpose is to cut strip into sheets and to classify it.

In some instances where it is desired only to pile the sheets, they arepassed through the classifier for the sole purpose of piling them. Theonly part of the classifier which is then used is one flight ofconveyors and one piling station. All of the sheets may be optionallydiverted at a classifying station alternatively to one piling stationand then to another piling station for convenient removal of full pilesof sheets.

Conventional classifiers are subject to many objections. As the speed ofthe sheets on conventional classifiers increases, they becomeprogressively more difiicult to handle, particularly when they transferfrom one conveyor to another. When the sheets are lapped and piled,

it is essential that their ends lap one above another in a regularpattern, both to avoid damage to the sheets and to avoid cobbles causedby improperly lapped sheets which will jam the entire classifier andspoil many of the sheets then in the classifier. These problems havelimited speeds of conventional classifiers to about 650 to 750 feet perminute. Although the machines have higher mechanical speeds, trouble isusually experienced during actual operating conditions when the speed ofsheets coming to the classifier exceeds the stated figure and issometimes encountered at lower speeds. The speed at which strip can behandled in a trimming line and through a shear is usually limited by thespeed at which the classifier itself can satisfactorily operate.Conventional classifiers frequently produce cobbles both when they arespeeding up to and slowing down from customary operating speeds. It isperiodically necessary to change blades and to make adjustments in theshears employed with sheet classifiers. The necessary placement of theclassifier adjacent to the shear limits access to the shear andincreases the difficulty of making necessary changes and adjustments.

I provide an entrance conveyor, at least one sheet classifying station,means to convey sheets from each classifying station to lap the sheetsand to pile them. I preferably provide a plurality of endless beltconveyors and magnetic means holding the sheets to said belts. I preferto provide magnetic sheet attracting means beneath the belts of theconveyors and extending along a substantial portion of their length. Iprovide magnetic sheet classifying means at each classifying station,preferably providing selectively operable magnetic sheet attractingmeans beneath the sheet pass line and magnetic sheet at tracting meansabove the sheet pass line. Preferably, I provide means to vary themagnetic fields adjacent the classifying stations in accordance with thedesired classification of the sheets. I provide magnetic means atconveyor transfer points spaced above the conveyors. I preferablyprovide sheet catching conveyors having magnetic sheet attracting meansshiftable longitudinally along the axis thereof. I provide a pluralityof conveyors to lap and pile sheets and having magnetic means associatedwith said conveyors and between said conveyors. I preferably provide apiling conveyor optionally extensible for varying sizes of sheets. Ifurther prefer to provide sheet piling guides which are longitudinallymovable, transversely movable and simultaneously transversely shiftable.

Other details, objects and advantages of my invention will becomeapparent as the following description of a present preferred embodimentof my invention proceeds.

In the accompanying drawings, I have illustrated a present preferredembodiment of my invention in which FIGURE 1 is a schematic elevationalview of a three pile classifier embodying my invention;

FIGURE 2 is a plan view of the classifier shown in FIGURE 1 showingsomewhat greater detail;

FIGURE 3 is a side view of the entrance conveyor and one of theclassifying stations taken in section;

FIGURE 4 is a plan view of the conveyors shown in FIGURE 3 without theoverhanging classifying apparatus and with some belt portions removed;

FIGURE 5 is a sectional view taken on line VV of FIGURE 3;

FIGURE 6 is a side view of a part of the classifier taken in section,overlapping FIGURE 3 and showing a second classifying station and one ofthe sheet lapping stations;

FIGURE 7 is a sectional View taken along line VII' VII of FIGURE 6;

FIGURE 8 is a plan view of one of the catching con-" veyors;

FIGURE 9 is a side elevational view of the conveyor shown in FIGURE 8;

FIGURE 10 is a partial sectional view taken on line XX of FIGURE 8;

FIGURE 11 is a partial sectional view taken on line XI-XI of FIGURE 8;

FIGURE 12 is a sectional view taken along line XII XII of FIGURE 1;

FIGURE 13 is a sectional view taken along line XIII XIII of FIGURE 1;

FIGURE 14 is a wiring diagram showing the circuits for some of theconveyor drive motors and electromagnets; and

FIGURE 15 is a wiring diagram schematically showing the circuit for oneof the magnetic classifying rolls.

General arrangement A sheet classifier embodying the invention isschematically shown in FIGURE 1. An entrance conveyor 1 receives sheetsfrom a shear and carries them away from the shear at a higher speed thanstrip entering the shear, thereby producing a spacing between sheets onconveyor 1. The sheets pass between pinch rolls which are asso ciatedand synchronized in speed with the shear. Sheets issuing from betweenpinch rolls 35 are deposited directly on entrance conveyor 1. Theconveyor is provided with three sheet piling stations 44, 46 and 47.Sheets which have pinholes are piled at station 44, sheets which areoffgauge are piled at station 46 and prime sheets are piled at station47. Sheets on conveyor 1 are carried to a classifying station at whichpoint they are classified, off-gauge and prime sheets passing to atransfer conveyor 2 and pinhole sheets going down the descending slopedsection 41 of conveyor 1. The pinhole sheets passing down slope 41 ofconveyor 1 will then pass to a lapping conveyor 11. They pass fromconveyor 11 through a lapping station indicated generally at 42 to acatching conveyor 12 on which the ends of consecutive sheets areoverlapped. The lapped sheets on conveyor 12 then pass through a stationindicated generally at 43 to piling conveyor 13. In passing fromconveyor 12 to conveyor 13, the sheets become overlapped to a greaterdegree than on conveyor 12. They are deposited by conveyor 13 at pinholepiling station 44. The prime and ofi-gauge sheets on conveyor 2 arecarried to a second classifying station indicated generally at 45.Off-gauge sheets are deflected to lapping conveyor 21 on the secondconveyor flight, thence to catching conveyor 22 and piling conveyor 23.Sheets proceeding along the second conveyor flight are formed in a pileat off-gauge piling station 46. Prime sheets are deposited on lappingconveyor 31 and are in like manner transferred to catching conveyor 32,piling conveyor 33 and piling station 47.

The classifier is shown in plan in FIGURE 2. Belt conveyors are usedthroughout the classifier, and, for convenience, the belts are dividedinto two belt sections which run side by side. The belts are identifiedthroughout by the same number as the associated conveyor with theletters a and b being used to designate the separate belt sections.Conveyors 48 are placed at floor level to carry piles of sheets awayfrom the piling stations.

7 The classifier which is illustrated is provided with three pilingstations. A classifier having the same general de tails of construction,but with difierent numbers of piling stations, could readily be employedby omitting one flight of conveyors or by adding additional flights.

The entrance conveyor Entrance conveyor 1 (FIGURES 3, 4, 5 and 6) ismounted on a base 111 in which a pivot pin 112 is pivotally mounted.Support 113 is mounted upon pivot pin 112 and has two cross members 114welded to it, which in turn support the side members 115 and 116 of theentrance conveyor frame. Two cross members 117 and 118 are attached toside members 115 and 116 adjacent the tail pulley end of the conveyor.The conveyor tail pulley comprises two halves 119a and 11% which arejournaled in bearings 1211a and 120b, respectively. Bearings 120a and12011 are mounted on bearing supports 121 which are slidably mounted incross member 117. The supports have threaded portions 122 formed ontheir end. Nuts 123 are placed on threads 122 leaving projecting endsextending through holes in cross member 118. Cross member 124 extendsbetween side members 115 and 116 adjacent classifying station 40. In thenormal position of the entrance conveyor, cross member 124 is injuxtaposition to plate 125 which is supported from base 126. Alignedholes in cross member 124 and plate 125 receive a bolt and nut 127. Theconveyor changes direction at magnetic roll 12% and terminates at a headpulley having two sections 129a and 12%. Conveyor side frames 130 extendbetween magnetic roll 128 and the conveyor head pulley. A sectional beltidler pulley 131 is located beneath magnetic roll 128 and supports andguides the belt sections returning from the head pulley to the tailpulley. A belt slack take-up comprises arms 132 which are supported fromside frames 115 and 116. A round bar 133 attached to arms 132 extendingacross the width of the conveyor actually engages the belt. The take-upis inoperative when the entrance conveyor is in normal position, butbecomes effective in belt take-up position when the conveyor is raisedas indicated at 148.

Under each belt half 1a and 117, two parallel pole pieces 134 and 135are mounted from brackets 137 attached to one of the cross members 114and to cross member 118. Two aprons 138 and 139 are attached above thepole pieces, one apron being positioned beneath each belt section. Aplurality of permanent horseshoe magnets 140 are fastened beneath eachpair of pole pieces 134 and 135 with all of the north poles of thehorseshoe magnets being placed against one of the pole pieces and all ofthe south poles being placed against the other pole piece. The polepieces maintain a strong magnetic field along the length of the conveyorand extend it virtually to the tail pulley. Additional pole pieces 141are positioned adjacent magnetic roll 128 with their ends extending frompole pieces 134 and 135 as closely as possible to magnetic I011 128.Magnetic roll 128 is hollow and has an electromagnet placed thereinwhich extends substantially throughout the length of the roll. Theelectromagnet comprises two pole pieces 142 and 143 on which coils 144are mounted at intervals. The electromagnet is mounted in a normallyfixed position and the outer shell of the roll is free to rotate. Theangular position of the electromagnet may be adjusted about the axis ofthe roll to change the line along which the magnetic field isconcentrated. Once the angular position of the pole pieces has beenfixed for a given installation, there will be little need to change it.On the section of conveyor 1 between magnetic roll 128 and head pulley129, pole pieces 145, aprons 146 and horseshoe magnets 147 are mountedin a manner similar to that which has been described. The pole piecesextend the field from magnetic roll 128 to head pulley 129.

It will be apparent that the portion of entrance conveyor 1 between thetail pulley and magnetic roll 128 can be rotated about pivot pin 112.When the conveyor is in the lowered position illustrated in FIGURE 3,its center of gravity will be between pivot pin 112 and the tail pulley.It is locked in this position by nut and bolt 127. The conveyor may bereadily moved to a raised position, shown in dotted outline 148, byremoving bolt and nut 127 and pushing upwardly adjacent the conveyortail pulley. When the conveyor has been lifted to its raised position148, the center of gravity will be between pivot pin 112 and magneticroll 128, and slot 149 in support 113 will be aligned with hole 150 inbase 111. A pin may be inserted therethrough to prevent the conveyorfrom being accidentally returned to ordinary operating position.Adequate clearance is then provided for repairs and adjustments to the:shear.

Transfer conveyor 2 (FIGURES 3, 4 and 6) is similar in details ofconstruction to entrance conveyor 1. It has side members 151 whichextend between classifying station 40 and classifying station 45. Amagnetic roll 152 is placed adjacent classifying station 45 and isidentical to magnetic roll 128. Conveyor 2 has a downwardly slopingportion which leads to the conveyor head pulley and lapping conveyor 21.It should be noted that side members 151 are fixed in position and thatconveyor 2 is not shiftable to a raised position. As with conveyor 1,the conveyor tail pulley may be adjusted for varying lengths of beltsections. The detailed arrangement of aprons, magnets and pole pieces issubstantially similar to that of conveyor 1.

The lapping conveyors The lapping conveyors 11, 21 and 31 are similar intheir details of construction. Lapping convey-or 11 (FIG- URES 6 and 7)is mounted upon bases 153 which are mounted on a sub-base 263 and whichsupport side members 154. The belt sections 11a and 11!) run over a headpulley having sections 155a and 15% mounted on a shaft 268 and a tailpulley having sections 156a and 156b, respectively. Apron plates 157,pole pieces 158 and horseshoe magnets 159 are provided similarly tothose already described. Tail pulley sections 156a and 15612 areadjustable in the same manner as those previously described. Shaft 268is journaled on the conveyor frame in a conventional manner. Lappingconveyors 21 and 31 are similar to lapping conveyor 11 except that ascan be seen from FIGURE 1, they are of greater length. The side members,belts, aprons and pole pieces are of. greater length and a larger numberof magnets is employed along the length of those conveyors.

The catching conveyors The catching conveyors 12, 22 and 32 are placedto receive lapped sheets from lapping conveyors 11, 21 and 31,respectively. The frame of catching conveyor 12 (FIGURES 6, 8, 9, and11) has two channel-shaped side members 49 and 59. A cross member 51extends between and supports side members 49 and 50 at the head pulleyend of the conveyor. Cross member 51 is sup ported from below by base53. Two cross members 54 and 55 extend between and support side members49 and 50 at the tail pulley end of conveyor 12 and are supported bybase 56. Two head pulley bearings 57 are supported from side members 49and 50 and have a head pulley shaft 58 journaled in them. The twoconvey-or belt sections 12a and 1212 run over head pulley sections 59aand 59b, respectively. The conveyor tail pulley is divided into twosections 69a and 601) which are separately journaled in bearings 61::and 61b. In the manner previously described, the tail pulley bearings61a and 6117 are mounted on support members 62 which are slidablymounted in holes drilled in cross member 54. Supports 62 have threadedportions 36 on which nuts 37 are placed. The projecting threaded ends 36extend through holes in cross member 54. Tail pulley sections 60a and605 may be adjusted by rotation of nuts 37 to compensate for variationsand irregularities in the length of belts 12a and 1212 due to wear andthe like.

A carriage is fitted between the upper and lower reaches of the beltsand between side members 49 and 50. The carriage comprises a bottomplate 63 hung from rollers 64 which travel on the lower flanges ofchannels 49 and 50. Four electromagnets 65, 66, 67 and 68 are mounted onbottom plate 63 of the carriage. An apron 69 is placed aboveelectromagnets 65 and 66 and a similar apron 70 is placed aboveelectromagnets 67 and 68. Aprons 69 and 70 are above the electromagnetsbetween them and the upper reach of the conveyor belt sec-tions. Threepermanent horseshoe magnets 71 are fastened adjacent the center line ofthe conveyor beneath belt sections 12b. The magnets are held firmly inposition between a pole piece 73 and a retainer 74 which are drawnagainst magnets 71 by bolts and are supported by supports 72. In likemanner, permanent horseshoe magnets 75 and their associated pole piece76 are positioned beneath belt section 12a. Additional magnets 77 andpole pieces 30 are supported beneath belt section-s 12a and 1212 frombottom plate 63 by supports 78 and 79. Magnets 77 are held to the polepieces by spring clips which have been omitted for purposes ofillustration, but which are of well-known conventional design.Additional pole pieces 81 are supported beneath belt section 1211 fromcross member 51 by bracket 52 and have horseshoe magnets 82 attached byconventional spring clips. A like set of pole pieces 83 and magnets 84is positioned on the opposite side of the conveyor center line beneathbelt section 12a. Electromagnets 85, S6, 87, 88, 89 and 96 are mountedbetween cross members 54 and 55 adjacent the tail pulley end of conveyor12. Electromagnets 85, 86 and 87 are supported from cross members 54 and55 by a cradle 91, and electromagnets 88, 89 and 90 are supported inlike manner by cradle 92.

A gearbox 93 is mounted on cross member 55 at the conveyor center line.It has an input shaft 94 and an output shaft 95. A shaft 96, having athreaded section 97, is attached to output shaft '95 and is journaled atits other end in cross member 51. A block 98 is threaded on shaft 96 andfits in hole 99 in the bottom plate 63 of the carriage. An electricmotor 100 mounted on side member 49 drives input shaft 94 through agearbox 101 and a connecting shaft 102. A spring-loaded brake band 193is continuously applied against a drum 104 mounted on an extension ofthe output shaft of gearbox 101. Rotation of motor 100 will cause thecarriage to move as desired between the position shown in FIGURE 8 andthe position generally indicated in dotted outline 105. TWo limitswitches 106 and 167 are mounted on side member 49 and are actuated by aramp 108 extending from bottom plate 63 of the carriage. They preventovertravel of the carriage by cutting power to motor 160 when thecarriage has reached the limit of its travel. A pointer 109 is mountedupon bottom plate 63 and may be read against a scale 110 which isconveniently calibrated for the length of sheets being handled in theclassifier.

Catching conveyor 22 is virtually identical to catching conveyor 12.Catching conveyor 32 has the same general construction as catchingconveyor 12 but is slightly moditied. It has a movable carriage havingthe same relationship to the tail pulley as is shown for conveyor 12. Inthe space between the carriage and the conveyor head pulley, a pair oflongitudinal pole pieces. is provided beneath each belt sectionextending from the limit of carriage travel to the conveyor head pulleyin a manner similar to that of conveyor 1. Thus, the carriage bears thesame relationship to the tail pulley in each case, but on conveyor 32,pole pieces and permanent horseshoe magnets of the type previouslydescribed extend from the carriage to the head pulley.

The support and drive assemblies The support and drive assembliesprovide support for the conveyors and supply power to the conveyorshafts. The assemblies are all substantially alike. Referring to FIGURE13, which is a view taken at classifying station 45, an upright frame264 having overhanging arms 265, 266 and 267 from top to bottom,respectively, is mounted upon subbase 263. As previously indicated, base153 of conveyor 11 is mounted upon subbase 263. The two sections oflapping conveyor head pulley 155a and 15517 are mounted on a shaft 268which is journaled on the conveyor frame as previously described.Universal joint 269 is attached to the end of shaft 268 and is connectedthrough an extensible drive shaft 270 to a universal joint 271. It willbe noted that shaft 270 and the two universal joints are connected tothe remainder of the drive train by couplings comprising opposed flanges272. Each pair of flanges is fastened together with bolts (notillustrated) which may be readily removed, thus breaking the flanges ofeither coupling. Universal joint 271 is driven by motor 273 (FIGURE 2)through a series of timing belts and countershafts in any convenientmanner. The motor, countershafts and timing are all separately mountedto one side of the classifier and drive through extensible drive shafts.A shaft 274 is journaled on brackets 275 (FIGURES 6 and 13) which aremounted on overhanging arm 267. Two tapered frusto-conical permanentmagnet rolls 276 are mounted upon shaft 274- above the belt sections ofconveyor 12. Rolls 276 are generally above the tail pulley of conveyor12, and their circumference is generally tangent to the upper surface ofconveyor 11. Shaft 276 is driven in the same manner as shaft 268. It isdriven in an opposite direction of rotation from shaft 268, and itsspeed is somewhat higher. The shaft speeds are adjusted to make thespeed of belts 12a and 12b and the tangential speed of rolls 276 equal.Guide plates 277 are placed on either side of rolls 276 and are nearlytangent to the rolls, with only a small part of the circumference ofrolls 276 projecting below guides 277 at any given time. Head pulleyshaft 278 of conveyor 2 is mounted on base 279 which rests on the upperface of overhanging arm 267. It is likewise driven by motor 273 througha series of belts and countershafts at the same speed as the head pulleyshaft of conveyor 1. Arm 266 also supports conveyor 31 below its tailpulley end. A shaft 280 is journaled on the lower side of overhangingarm 265. Two cylindrical magnetic rolls 281 are mounted on the shaftgenerally tangent to the upper surfaces of conveyors 2 and 31. Shaft28%) is driven through similar drive means by motor 273. Guide plates282 are fixed on either side of rolls 281 and only a small part of thecircumference of rolls 281 is below guide plates 282 at any givenmoment. A divider 283 having a narrow pointed edge 284 is positionedbeneath rolls 281 and extends substantially the Width of the conveyors.It is mounted on frame 264 by conventional means (not illustrated) andis pivotally movable about a pivot point 285.

FIGURE 12 illustrates the suspension of the conveyors at another pointalong the line. As can be seen from FIGURE 12, the mounting of theconveyors is similar to that already described and the figure need notbe described in detail. It is apparent, however, that the variousconveyor and magnet roll shafts are driven through a system of drivebelts and countershafts similar to those which have been described andillustrated.

A plurality of electric motors are provided to drive the conveyors. Ineach instance the head pulley of the conveyor is driven, and theremaining pulleys on the conveyor are merely idlers which are driven bythe belts. The overhead magnetic rolls associated with each conveyor aredriven with their tangential speeds being equal to the linear speed ofthe belts on the associated conveyor. They are, of course, driven withan opposite direction of rotation from the conveyor shafts, and a sheetpassing between them will be urged forwardly by both the magnet rollsand the conveyor belts toward the piling stations. Conveyors 1, 2 and 11and their associated magnet rolls are driven by motor 273. The remainingconveyors and their associated magnet rolls are driven by motors 286,287, 288, 289, 290, 291 and 292.

The magnetic controls A schematic wiring diagram of the magnet and motorcircuits is shown in FIGURE 14. A constant line voltage is appliedacross conductors 293 and 294. A motor bus bar 295 is connected toconductor 293 through a variable resistor 296. A magnet bus bar 297 isconnected to conductor 293 through a variable resistor 298. Resistors296 and 298 are ganged for single control. The shear motor speedcontroller is also operated with resistors 296 and 298. Motor 273 isconnected between motor bus bar 295 and conductor 294, and a separatecontrol resistor 299 is provided in series with that motor. The

remaining conveyor drive motors except the piling conveyor drive motorsare connected in similar manner between bus bar 295 and conductor 294,and separate speed regulators are provided for each motor. The pilingconveyor drive motors are separately controlled.

The coils of the fixed electromagnets 85, 86, 87, 88, 89 and 96 mountedon catching conveyor 12 are connected in parallel between magnet bus bar297 and conductor 294. Magnets 85, 86 and 87 are supplied through acurrent limiting resistor 301i and a variable resistor 301. Magnets 83,89 and 91 are similarly supplied through a current limiting resistor 302and a variable resistor 363. Both groups are supplied from a masterrheostat 304 which will vary the current to all of the magnets 85, S6,87, 88, 89 and simultaneously. Resistor 301 will simultaneously vary thecurrent to magnets 85, 86 and 87, and resistor 313-3 will simultaneouslyvary the current to magnets 88, 89 and 90. A switch 305 is provided todisconnect all of the fixed catching conveyor magnets from magnet busbar 297. In a similar fashion, the catching conveyor movableelectromagnets 65 and 66 are placed in parallel and are supplied througha current limiting resistor 306 and a variable resistor 307. Magnets 67and 68 are similarly paralleled through current resistor 308 andvariable resistor 309. Both pairs of magnets are supplied through amaster rheostat 310 and a switch 311.

The lapping conveyor electromagnets 168, 169, 170, 171, 172 and 173 areconnected between magnet bus bar 297 and conductor 294' in a manneridentical to the fixed catching conveyor magnets. A variable resistor312 controls magnets 168, 169 and 170. A variable resistor 313 controlsmagnets 171, 172 and 173, and a master rheostat 314 controls all of thepiling conveyor electromagnets. A switch 315 is provided to disconnectall of the catching conveyor electromagnets.

It is to be understood that the electromagnets of catching conveyors 22and 32 and of piling conveyors 23 and 33 are connected between magnetbus bar 297 and conductor 294 in a manner similar to that which has beendescribed for the magnets on conveyors 12 and 13.

A schematic wiring diagram showing the control circuit for magnet roll128 is illustrated in FIGURE 15. The roll is powered from two linecurrent conductors 317 and 318. A relay 319 is connected to the pinholedetecting means through a suitable time delay mechanism by leads 320.When relay 319 is energized, it will close normally open switch 321connecting coils 144 of magnet roll 128 between the line connections 317and 318. Two parallel branches are provided between coils 144 and line318. One branch passes through normally closed switch 322, and the otherbranch passes through fixed resistor 323 and variable resistor 324. Whenswitch 321 is closed, it will also energize timer 325. When the timer isenergized, it will, after a fixed interval, energize relay 326 therebyopening switch 322 and leaving the sole connection for coils 144.through resistors 323 and 324. Timer 325 will hold switch 322 in openposition until switch 321 opens thereby resetting timer 325.

Operation In readying the classifier for operation, the conveyor motorcontrols are adjusted to run the motors and shear at the desired speed.The motors for entrance conveyor 1, transfer conveyor 2, the lappingconveyors and the catching conveyors are all run at approximately thesame speed and they are simultaneously varied with the speed of theshear. Entrance conveyor 1 and the others are driven somewhat fasterthan the strip entering the shear to provide a preferred spacing ofthree or four inches between sheets on entrance conveyor 1. The catchingconveyors are driven at approximately one-half the speed of thepreceding lapping conveyors. The piling conveyors are driven at aconstant speed to produce good piling, usually at about 250 feet perminute.

The classifier may, of course, handle sheets of varying width and lengthwhose size will be dependent upon the width of strip and the length ofcut of the shear. The movable carriage of catching conveyor 12 isadjusted for the proper sheet length. Preferably, the distance frommagnet rolls 276 to the center of electromagnets 65, 66, 67 and 68 isapproximately equal to the length of sheet being handled by theclassifier. Scale 110 is calibrated in inches for varying sheet lengths,and the carriage is adjusted until pointer 109 is opposite the desiredscale mark. The carriages of catching conveyors 22 and 32 are similarlyadjusted. The carriage drive motors on the catching conveyors aresimultaneously controlled from a control panel, and the carriages on allof the catching conveyors are thus shifted simultaneously. Individualmotor controls for fine adjustment of the separate carriages are alsoprovided.

After the initial adjustments have been made to the classifier, strip isfed to the shear. The speed of strip feed, of the shear and of theclassifier are all controlled by a master controller. As the strippasses into the shear, it is cut into sheets which pass between pinchrolls 35 and are deposited upon entrance conveyor 1. Conveyor 1 isoperated at a somewhat higher speed than the shear to maintain a spaceof three or four inches between each sheet on conveyor 1. It will beunderstood that the strip has been inspected for pinholes and thicknessby wellknown means prior to being sheared. Where sections of the stripwhich are off-gauge or which have pinholes are detected, a time delaymechanism will be actuated to separate the resulting pinhole andoff-gauge sheets at classifying stations 40 and 45. Sections of thestrip having pinholes will be detected prior to the time the stripenters the shear. Suitable and well-known time delay means synchronizedto the speed of strip passing through the shear and classifier willenergize relay 319 as the leading end of the sheet having pinholesapproaches magnetic roll 128. The action of relay 319 will close switch321 and place the full voltage across conductors 317 and 318 on coils144. After the magnetic field has become saturated, timer 315 will openswitch 322, reducing the current through coils 144. After the last sheethaving pinholes has passed roll 128, the power relay 319 will be cut oilallowing switch 321 to reopen. Magnetic roll 152 is energized in asimilar manner to deflect olf-gauge sheets to the middle flight ofconveyors.

As each sheet issues from pinch rolls 35 over the tail pulley ofconveyor 1, it will be attracted to the conveyor by horseshoe magnets148. The magnetic field is carried very close to the conveyor tailpulley by pole pieces 134. The pole pieces likewise extend the magneticfield toward magnetic roll 128. Sheets having pinholes are diverted atclassifying station 40 and pass to the lower flight comprising conveyors11, 12 and 13. As the leading end of a pinholed sheet approachesmagnetic roll 128, the coils will be energized as has been described.The magnetic attraction at roll 128 is concentrated between the tips ofpole pieces 142 and 143, and the magnetic attraction will firmly drawthe leading edge of the sheet having pinholes to the conveyor belt.Urged by the magnetic attraction, the sheet will follow the curvature ofmagnetic roll 128 and will go down the sloping section 41 of conveyor 1toward lapping conveyor 11. Magnets 147 and the associated pole pieces145 create a strong magnetic field extending immediately from magneticroll 128 to entrance conveyor head pulley. The magnets act to hold thesheet firmly to the sloping belt sections. Should the next succeedingsheet also have pinholes, the control means will maintain the current incoil 144 of magnetic roll 128, and the next sheet will in like mannerfollow the curve of the conveyor belt around magnetic roll 128 down thesloping portion 41 of entrance conveyor 1. Succeeding sheets havingpinholes will follow in like manner. As the first sheet reaches the headpulley of conveyor 1, it will continue in its line of direction untilthe leading end hits lapping conveyor 11 and is deflected onto 10 beltsections 11a and 11b. Lapping conveyor 11 is driven at the same speed asentrance conveyor 1 and there will be a smooth transfer without slidingbetween the sheet and the belts as the sheet changes direction.

Permanent magnets 159 and pole pieces 158 create a magnetic fieldextending from the tail pulley to the head pulley of conveyor 11. As theleading end of a sheet is projected from conveyor 1 toward conveyor 11,the leading end will be drawn toward conveyor 11 while the trailing endremains on the slope 41 of conveyor 1. As more of the sheet istransferred to lapping conveyor 11, the sheet will be more firmlyattracted to the belt sections of conveyor 11. The trailing end willthen leave entrance conveyor 1, and the sheet will be entirely upon thelapping conveyor 11. The spacing between entrance conveyor 1 and lappingconveyor 11 is sufficiently close that the shortest sheet handled by theclassifier will never be out of the magnetic attraction of at least oneconveyor while it is transferring between the conveyors. As the sheet iscarried along lapping conveyor 11, it will be held continuously andfirmly to the conveyor belt sections by magnets 159. As the sheetreaches the conveyor head pulley, its leading end will be projectedbeyond the head pulley.

The sheets are of relatively thin gauge, and as each is projected beyondthe head pulley above catching conveyor 12, its natural tendency will beto droop. The leading end, however, will come within the field ofmagnetic rolls 276 which will draw the leading end of the sheet towardit. Guide plates 277 prevent the sheet from wrapping around or hittingheadlong into magnetic rolls 276 and will keep it generally tangent tothe rolls. The rolls will contact and lift the sheet near its edges, butthe center of the sheet will be unsupported and will fall slightly,giving the sheet a concave upper surface and providing a certain amountof stiffness.

As the leading end of the sheet passes beyond rolls 276, it will comewithin the magnetic field produced by electromagnets 85, 86, 87, 88, 89and 98. The sheet will, however, have transverse stiffness by virtue ofits concave, shape and will be projected above conveyor 12. Rolls 276,which are driven with a tangential velocity equal to the belt speed ofconveyor 11, will project the sheets outwardly over conveyor 12 at asustained speed. The belt sections of lapping conveyor 12, however, aredriven at about one-half the speed of conveyor 11. Thus, the sheet willbe traveling considerably faster than belt sections 12a and 12b. As theleading end of the sheet passes beyond the head pulley of conveyor 11,the sheet will remain generally out of contact with belt sections 12aand 12b and will be principally under the control of magnet rolls 276.As the trailing end of the sheet reaches magnet rolls 276 and passesbeyond them, the sheet will no longer be held in a bowed position, andthe trailing end will be pulled by electromagnets 85, 86, 87, 88, 89 and90 firmly onto conveyor belt sections 12a and 1212. At this point, theleading end of the sheet will be approximately above electromagnets 65,66, 67 and 68. The sheet will, therefore, be pulled into firm contactwith the conveyor belt sections 12a and 12b at its leading and trailingends at approximately the same moment. In view of the fact that thesheet is traveling approximately twice as fast as the conveyor beltsections, there will be a certain amount of sliding until frictionbetween the belt sections and the sheet brings it to rest on the belt.The sheet is always under the control of at least one set of magnetswhile it is transferring from conveyor 11 to conveyor 12. The next sheetimmediately behind will react in the manner just described. After asheet is on the belts of conveyor 12, it will move at a slower speedthan the sheet immediately behind. The leading end of the faster movingfollowing sheet will be projected outwardly and will overlap thepreceding sheet. The magnetic field of magnets 85, 86, 87, 88, 89 and 90will be largely shunted by the sheet which is on the conveyor 12 whichwill further add to the tendency of the following sheet to cantileverabove conveyor 12. The trailing end of the sheet on conveyor 12 willpass beyond magnets 85, 86, 87, 88, 89 and 90 while the next followingsheet is still in contact with magnet rolls 276. When the trailing endof the cantilevered sheet passes beyond magnet rolls 276, it will befirmly and quickly drawn to conveyor 12 by the fixed electromagnets. Inthis manner, successive sheets are overlapped one upon another as theypass from the conveyor 11 to conveyor 12.

The sheets may be delivered on the conveyors in an oblique or twistedposition. It is desirable to align them with the conveyor for smooth andeasy piling. The obliqueness or skew may be corrected by imposing anuneven magnetic drag upon the sheet. Preferably, the magnetic pull ordrag is increased on the side of the sheet which is advanced over theother. In the first conveyor flight, variable resistors 301 and 303, 307and 309, and 312 and 313 may be used for this purpose. Principally, theadjustment is made to resistors 301 and 303 thereby affecting therelative strength or pull of the groups comprising magnets 85, 86 and 87and magnets 88, 89 and 90. Supplemental adjustments may be made byvarying the pull of the other groups of electromagnets.

As the lapped sheets are carried along catching conveyor 12, they willbe held firmly to the conveyor belt by the electromagnets, permanentmagnets and pole pieces beneath the belt sections, and they will becarried to the end of the catching conveyor. The first sheet willtransfer from catching conveyor 12 to piling conyevor 13 in the samemanner in which it transferred from lapping conveyor 11 to catchingconveyor 12.

Frequently, only a single isolated sheet having pinholes is deflected atclassifying station 40. At such times the single sheets will pass alongconveyors 11, 12 and 13 in the manner described but will not, of course,be lapped with other sheets. At times a single sheet and the secondsheet behind it may be deflected because of pinholes. In this case, thesheets may be lapped as they transfer from catching conveyor 12 topiling conveyor 13.

As sheets which do not have pinholes approach classifying station 40,magnetic roll 128 will not be energized, and the sheets Will passdirectly to transfer conveyor 2. Magnets on transfer conveyor 2 willhold the sheets firmly on the belts and carry them to classifyingstation 45. At classifying station 45, sheets which are off-gauge aredeflected to conveyors 21, 22 and 23 and piling station 46. They arehandled along conveyors 21, 22 and 23 in the same manner that pinholesheets are handled along conveyors 11, 12 and 13. Prime sheets which arenot offgauge and do not have pinholes will continue through classifyingstation 45 along conveyors 31, 32 and 33 to piling station 47, beinghandled in the same manner as reject sheets.

Prime and off-gauge sheets Will be handled at classifying station 45.Magntic roll 152 at classifying station 45 is identical to magnetic roll128 which has already been described. Magnet rolls 281 are supportedbeyond and above magnetic roll 152 but short of the tail pulley ofconveyor 31. Rolls 281 are driven with their tangential speed equal tothe speed of conveyor 2. As prime sheets on conveyor 2 approach magneticroll 152, the coils within magnetic roll 152 will be de-energized. Thesheets will be firmly held to conveyor 2 by the permanent magnets in themanner previously described until they are virtually at magnetic roll152. In the absence of any pull from magnetic roll 152, the leading endof the sheet will continue in approximately the same direction and willhave its leading end projected outwardly toward conveyor 31. The leadingend of the sheet will very quickly come within the magnetic field ofmagnet rolls 281 which will lift the leading end of the sheet towardguide plates 282. The sheet will be generally tangent to magnet rolls281 and will be lifted by it and carried forward. As the leading end ofthe sheet passes beyond magnet rolls 281, it will shortly thereaftercome Within the field of the permanent magnets on conveyor 31. Theleading end will then be pulled downwardly to belt sections 31a and 31band carried along the belt. Any given section of a prime sheet willtherefore be successively held down on conveyor 2, lifted by magnetrolls 281 and held down onto conveyor 31. At a given moment, the leadingend of a prime sheet may be held to conveyor 31 by the permanent magnetsthereunder, the middle section lifted to magnet rolls 281 and thetrailing end held to conveyor 2 by the permanent magents thereunder. Thesheet is under control of the magnets at all times in transferring fromconveyor 2 to conveyor 31 and is successively pulled downwardly, thenupwardly and then downwardly. Divider 283 remains in a fixed positionand does not operate to direct sheets to different conveyors. Itprincipally serves to channel the sheets in one direction or anotherafter the initial classification or split has been made. It furtherserves to protect the tail pulley and belts of conveyor 31 shouldcontrol of magnetic roll 152 fail while the classifier is in operation.

Classifying station 40 is identical to and operates in the same manneras classifying station 45 except that pinhole sheets on the one hand areseparated from prime and off-gauge sheets on the other hand atclassifying station 40, whereas, at classifying station 45, off-gaugesheets are separated from prime sheets.

The velocity of the sheets will vary with the speed of the classifier,which will be frequently adjusted during operations because ofvariations in the speed with which strip may be fed to the shear. Thekinetic energ of the sheets and consequently the amount of energy whichmust be absorbed in reducing the speed of the sheet-s and piling themwill vary as the square of the ve locity. It has been found that if theelectromagnets strong enough to stop the sheets at full speed are employed at the belt transfer points, the sheets will be so firmly held tothe conveyor at low speed that it is impossible to make a satisfactorytransfer and lapping operation. The ends of the sheets cannot beprojected outwardly above the preceding sheets. The electromagnets aredesigned to operate below the saturation point in the range where theflux density will be proportional to the magnetizing current. The pullof the magnets is proportional to the square of the flux density or tothe square of the magnetizing current. As has been previously pointedout, the current to the coils of the electromagnets Will be varied withthe speed of the line. Thus, the magnetic field of the electromagnetswill vary directly with the kinetic energy of the sheets. After theinitial adjustment has been made, the magnets will automatically providethe necessary pull at any classifier speed.

The tension of the conveyor belt sections may be regulated by adjustmentof the associated tail pulley section. After the proper adjustment fortension has been made, the belt may be made to track properly byincreasing or decreasing the tension on one side of the belt only. Fromtime to time, it will be necessary to replace worn belts. To remove abelt section, the associated tail pulley section is backed off toproduce slack in the belt. The belt sections on the side away from thedrive motors may be readily slipped off, and a new belt installed andadjusted. Before removing belt sections on the side nearest the drivemotors, it is first necessary to break one of the couplings connecteingthe belt head pulley to the drive means. The drive shaft is then swungout of the way, and the belt may be readily removed and replaced.

From the foregoing, it will be apparent that I have inventioned new anduseful methods and apparatus for classifying and piling sheets. Thesheets are kept in close control at all times and cobbles ormalfunctioning due to sheets which are out of control is virtually eliminated. The classifier will operate satisfactorily at any desired speedand its operation is not critical while attaining a desired operatingspeed or while the operating speed 13 is being changed. It will operatesatisfactorily at much higher speeds than those which could be obtainedby previous classifiers and has been operated satisfactorily at speedsin excess of two thousand feet per minute.

While I have described a present preferred embodiment of my invention,it will be understood that I do not limit myself thereto and that myinvention may be otherwise variously practiced within the scope of thefollowing claims.

I claim:

1. In a sheet classifier, a sheet catching conveyor having endless beltstraveling over tail pulley means toward head pulley means, a pluralityof magnets positioned beneath the belts and spaced laterally across theconveyor adjacent the tail pulley means, a second plurality of magnetspositioned beneath the belt and spaced away from the tail pulley towardthe head pulley means, and means to vary the pulling strength of some ofsaid magnets simultaneously with variation in speed of the conveyor.

2. In a sheet classifier, a sheet catching conveyor having endless beltstraveling over tail pulley means toward head pulley means, a pluralityof magnets positioned beneath the belts and spaced laterally across theconveyor adjacent to the tail pulley means, means to vary the pullingstrength of said magnets proportionally with the kinetic energy ofsheets on the conveyor, and a second plurality of magnets longitudinallymovable along the conveyor beneath the belts.

3. In a sheet classifier, a sheet catching conveyor having endless beltstraveling over tail pulley means toward head pulley means, a pluralityof electro-magnets psitioned beneath the belts and spaced laterallyacross the conveyor adjacent to the tail pulley means, a movablecarriage mounted on the framework of said conveyor beneaththe belts, aplurality of electro-magnets mounted on said carriage, and means to varythe pulling strength of all said electro-magnets simutaneously with thespeed of the conveyor.

4. In a sheet classifier, a sheet catching conveyor having endless beltstraveling over tail pulley means toward head pulley means, a pluralityof electro-magnets positioned beneath the belts and spaced laterallyacross the conveyor adjacent to the tail pulley means, a carriagemovable axially along the framework of the conveyor beneath the belts, aplurality of electro-rnagnets mounted on the conveyor, means to vary thepulling strength of said electr-o-magnets proportionally to the kineticenergy of sheets being transported on said conveyor, and additionalmagnets mounted on the carriage.

5. In a sheet classifier, a sheet catching conveyor having endless beltstraveling over tail pulley means toward head pulley means, a pluralityof electro-magnets positioned beneath the belts and spaced laterallyacross the conveyor adjacent to the tail pulley means, a movablecarriage mounted on the framework of said conveyor beneath the belts, aplurality of electro-magnets mounted on said carriage, a plurality ofmagnets positioned beneath the belts adjacent to the head pulley means,and means to vary the pulling strength of all of said electromagnetssimultaneously with the speed of the conveyor.

References Cited by the Examiner UNITED STATES PATENTS 1,490,594 4/24Lateur.

1,589,091 6/26 Barber 198l21 1,597,778 8/26 Fisk.

2,008,200 7/35 Clauss 19841 2,291,261 7/42 Taylor 198--41 2,642,174 6/53Buccicone 198-41 2,697,506 12/54 Snyder 198-41 X 2,762,492 9/56 HopkinsW l98l39 2,788,116 4/57 Wood 198139 2,792,103 5/57 Piemont 198-121SAMUEL F. COLEMAN, Primary Examiner.

ERNEST A. FALLER, EDWARD A. SROKA,

Examiners.

1. IN A SHEET CLASSIFIER, A SHEET CATCHING CONVEYOR HAVING ENDLESS BELTSTRAVELING OVER TAIL PULLEY MEANS TOWARD HEAD PULLEY MEANS, A PLURALITYOF MAGNETS POSITIONED BENEATH THE BELTS AND SPACED LATERALLY ACROSS THECONVEYOR ADJACENT THE TAIL PULLEY MEANS, A SECOND PLURALITY OF MAGNETSPOSITIONED BENEATH THE BELT AND SPACED AWAY FROM THE TAIL PULLEY TOWARDTHE HEAD PULLEY MEANS, AND MEANS TO VARY THE PULLING STRENGTH OF SOME OFSAID MAGNETS SIMULTANEOUSLY WITH VARIATION IN SPEED OF THE CONVEYOR.